Conventional indoor plant cultivation operations are known to use indoor or artificial lighting systems to provide ultraviolet (UV) and/or infrared (IR) radiation to plants as a means for simulating sunlight, heat and desired growing conditions. In known embodiments, plants at various stages of their lifecycle are provided in a substantially horizontal arrangement, such as provided in pots distributed on a floor or elevated horizontal surface. In such arrangements, lighting elements are generally provided above the plants and direct or radiate light downwardly to the plants. Such systems are limited in that the number of plants that can be cultivated are limited by the area of the space and over-crowding concerns, as well as the fact that downwardly-directed light may not provide the ideal or desired exposure to the plants.
With respect to illumination, a typical plant grow light produces light wavelengths from 380 nm (UV) up to and beyond 880 nm (IR), however, plants only use certain groups of light wavelengths from the visible light spectrum (400 nm-700 nm). The wavelengths associated with green and yellow colors appear brighter to the human eye than red and blue colors, which are the primary colors used by plants for photosynthesis. Incandescent and fluorescent lighting are designed to light rooms but not necessarily design to be used as plant grow lights. In the past, manufacturers modified incandescent and fluorescent light bulbs and added impurities to get more of the colors that plants need to grow. As much as 82% of the light coming out of a typical plant light is not absorbed by plants or is in the form of UV light or heat.
LED grow lights offer an alternative to incandescent and fluorescent lights. For example, LED grow lights use LEDs that generate more of the particular colors of light needed to target wavelengths for plant growth. Thus, growers are able to use several colors of LEDs and select particular colors depending on the crop growing. Thus, LED grow lights are more efficient than incandescent and fluorescent lights by eliminating colors of light that are not required for plant growth.
The light from existing LED light bars is emitted in a cone shape from above the plants. Mounting the bars too close to plants will prevent the light from individual LED clusters, or sets of RGB (red, green, blue) LED lights, from blending properly before reaching the plant canopy. While coverage area increases as the LED grow lighting is moved further from the plant canopy, the light intensity decreases. When using multiple light bar arrays, increasing the distance from the plant canopy allows clusters from multiple light bars to overlap.
However, placing a light bar above of the plant canopy does not allow sufficient light to reach the lower portions of plants, nor is the light bar effective in a vertical growing system. Accordingly, there is a need for a system that provides sufficient light to plants from the canopy to the lower portions of the plant, and also provides sufficient light to plants growing in a vertical system.